//go:build linux && rootrunner

package host

import (
	"os"
	"os/exec"
	"path/filepath"
	"strconv"
	"testing"

	"github.com/carlosframework/platform/internal/release"
	"github.com/carlosframework/platform/internal/rootstate"
)

func TestPlan14GenerationKernelRetirementRootRunner(t *testing.T) {
	dir := os.Getenv("PLAN14_E25_RETIRE_KERNEL_CHILD")
	if dir == "" {
		dir = generationRootRunnerDir(t)
		cmd := exec.CommandContext(t.Context(), "unshare", "--mount", "--pid", "--fork", "--mount-proc", os.Args[0], "-test.run=^TestPlan14GenerationKernelRetirementRootRunner$", "-test.count=1")
		cmd.Dir = dir
		cmd.Env = append(os.Environ(), "PLAN14_E25_RETIRE_KERNEL_CHILD="+dir)
		if out, err := cmd.CombinedOutput(); err != nil {
			t.Fatalf("isolated root retirement: %v %s", err, out)
		}
		return
	}
	t.Setenv("CARLOS_OPT_DIR", dir)
	path := release.VersionPath(dir, "bab", "v1", "shop")
	if err := os.MkdirAll(filepath.Dir(path), 0755); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(path, []byte("retained generation"), 0644); err != nil {
		t.Fatal(err)
	}
	identity := func(path string) rootstate.FileIdentity {
		t.Helper()
		file, err := os.Open(path)
		if err != nil {
			t.Fatal(err)
		}
		defer file.Close()
		id, err := rootstate.Identity(file)
		if err != nil {
			t.Fatal(err)
		}
		return id
	}
	k := generationKernel{proc: "/proc"}
	boot, err := k.boot()
	if err != nil {
		t.Fatal(err)
	}
	controller := exec.CommandContext(t.Context(), "/bin/sleep", "60")
	controller.Dir = dir
	if err := controller.Start(); err != nil {
		t.Fatal(err)
	}
	joined := false
	t.Cleanup(func() {
		if !joined {
			_ = controller.Process.Kill()
			_ = controller.Wait()
		}
	})
	raw, err := generationRead(filepath.Join("/proc", strconv.Itoa(controller.Process.Pid), "stat"))
	if err != nil {
		t.Fatal(err)
	}
	start, err := generationStart(raw)
	if err != nil {
		t.Fatal(err)
	}
	r := release.GenerationReservation{Binding: release.GenerationBinding{
		Binding: release.HistoryBinding{Host: filepath.Base(dir) + ".example", Account: "bab", App: "shop"},
		Target:  release.GenerationOwner{BootID: boot}, Version: "v1", Path: path, Tree: filepath.Dir(path),
		Executable: identity(path), TreeIdentity: identity(filepath.Dir(path)),
		ControllerPID: controller.Process.Pid, ControllerStart: start,
	}}
	if _, err := productionGenerationAbsence(t.Context(), r); err == nil {
		t.Fatal("live controller released")
	}
	if err := controller.Process.Kill(); err != nil {
		t.Fatal(err)
	}
	_ = controller.Wait()
	joined = true
	if digest, err := productionGenerationAbsence(t.Context(), r); err != nil || len(digest) != 64 {
		t.Fatalf("joined controller: %s %v", digest, err)
	}
	file, err := os.Open(path)
	if err != nil {
		t.Fatal(err)
	}
	if _, err := productionGenerationAbsence(t.Context(), r); err == nil {
		file.Close()
		t.Fatal("controller join erased an open reference")
	}
	file.Close()
	if err := os.Rename(filepath.Dir(path), filepath.Dir(path)+".old"); err != nil {
		t.Fatal(err)
	}
	if err := os.Mkdir(filepath.Dir(path), 0755); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(path, []byte("replacement"), 0644); err != nil {
		t.Fatal(err)
	}
	if _, err := productionGenerationAbsence(t.Context(), r); err == nil {
		t.Fatal("replaced staged tree discharged the original identity")
	}
}